feat: added ghost user

Author: raphael-goetz

app/models/concerns/namespace_parent.rb

@@ -4,7 +4,7 @@ module NamespaceParent
   extend ActiveSupport::Concern
 
   included do
-    has_one :namespace, as: :parent
+    has_one :namespace, as: :parent, dependent: :destroy
   end
 
   def ensure_namespace

app/models/user.rb

@@ -3,6 +3,9 @@
 class User < ApplicationRecord
   include NamespaceParent
 
+  GHOST_USERNAME = 'ghost'
+  GHOST_EMAIL = 'ghost@code0.tech'
+
   has_secure_password
 
   validates :username, length: { maximum: 50 },
@@ -31,6 +34,17 @@ class User < ApplicationRecord
 
   has_one_attached :avatar
 
+  before_destroy :prevent_destroy_ghost_user, prepend: true
+  before_destroy :reassign_authored_audit_events_to_ghost_user
+
+  def self.ghost
+    find_by!(username: GHOST_USERNAME)
+  end
+
+  def ghost?
+    username == GHOST_USERNAME
+  end
+
   def mfa_enabled?
     totp_secret != nil
   end
@@ -68,6 +82,23 @@ def validate_mfa!(mfa)
   generates_token_for :password_reset, expires_in: 15.minutes do
     password_digest&.last(20)
   end
+
+  private
+
+  def prevent_destroy_ghost_user
+    return unless ghost?
+
+    errors.add(:base, :invalid, message: 'Cannot delete ghost user')
+    throw :abort
+  end
+
+  def reassign_authored_audit_events_to_ghost_user
+    ghost_user = self.class.ghost
+
+    authored_audit_events.find_each do |audit_event|
+      audit_event.update!(author: ghost_user)
+    end
+  end
 end
 
 User.prepend_extensions

app/services/users/delete_service.rb

@@ -18,6 +18,7 @@ def execute
 
       transactional do |t|
         namespace = user.namespace
+        audit_author_id = user == current_authentication.user ? User.ghost.id : current_authentication.user.id
 
         user.destroy
 
@@ -41,7 +42,7 @@ def execute
 
         AuditService.audit(
           :user_deleted,
-          author_id: current_authentication.user.id,
+          author_id: audit_author_id,
           entity: user,
           target: AuditEvent::GLOBAL_TARGET,
           details: {}

db/fixtures/01_application_settings.rb

@@ -1,5 +1,12 @@
 # frozen_string_literal: true
 
+User.seed_once :username do |u|
+  u.username = User::GHOST_USERNAME
+  u.email = User::GHOST_EMAIL
+  u.password = SecureRandom.hex
+  u.admin = false
+end
+
 ApplicationSetting.seed_once :setting do |s|
   s.setting = :user_registration_enabled
   s.value = false

db/fixtures/production/01_users.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-return unless User.none?
+return unless User.where.not(username: User::GHOST_USERNAME).none?
 
 initial_root_email = ENV.fetch('INITIAL_ROOT_MAIL', nil)
 initial_root_password = ENV.fetch('INITIAL_ROOT_PASSWORD', SecureRandom.hex)

spec/requests/graphql/query/users_query_spec.rb

@@ -19,9 +19,7 @@
   end
 
   before do
-    create(:user)
-    create(:user)
-    create(:user)
+    create_list(:user, 3)
 
     post_graphql query, current_user: current_user
   end
@@ -46,7 +44,10 @@
     let(:current_user) { create(:user, :admin) }
 
     it 'returns all users' do
-      expect(graphql_data_at(:users, :nodes)).to have_attributes(length: 4)
+      expected_ids = User.all.map { |user| user.to_gid.to_s }
+      returned_ids = graphql_data_at(:users, :nodes).pluck('id')
+
+      expect(returned_ids).to match_array(expected_ids)
     end
   end
 end

spec/services/users/delete_service_spec.rb

@@ -9,6 +9,9 @@
 
   let(:user) { create(:user) }
   let(:current_user) { create(:user, :admin) }
+  let!(:ghost_user) do
+    create(:user, username: User::GHOST_USERNAME, email: User::GHOST_EMAIL)
+  end
 
   it 'deletes the user successfully' do
     namespace_id = user.ensure_namespace.id
@@ -31,6 +34,65 @@
     )
   end
 
+  context 'when the user authored audit events' do
+    let!(:audit_event) do
+      create(:audit_event,
+             author: user,
+             action_type: :user_logged_in,
+             entity: user,
+             target: AuditEvent::GLOBAL_TARGET)
+    end
+
+    it 'reassigns authored audit events to the ghost user' do
+      expect { service_response }.to change { User.exists?(user.id) }.from(true).to(false)
+      expect(service_response).to be_success
+      expect(audit_event.reload.author).to eq(ghost_user)
+    end
+  end
+
+  context 'when the user owns a namespace' do
+    let!(:namespace) { user.ensure_namespace }
+    let!(:project) { create(:namespace_project, namespace: namespace) }
+    let!(:flow) { create(:flow, project: project) }
+
+    it 'deletes the owned namespace and associated projects and flows' do
+      expect { service_response }
+        .to change { Namespace.exists?(namespace.id) }.from(true).to(false)
+        .and change { NamespaceProject.exists?(project.id) }.from(true).to(false)
+        .and change { Flow.exists?(flow.id) }.from(true).to(false)
+
+      expect(service_response).to be_success
+    end
+  end
+
+  context 'when deleting the current user' do
+    let(:user) { current_user }
+
+    it 'creates the deletion audit event with the ghost user as author' do
+      expect(service_response).to be_success
+
+      is_expected.to create_audit_event(
+        :user_deleted,
+        author_id: ghost_user.id,
+        entity_type: 'User',
+        entity_id: user.id,
+        details: {},
+        target_type: 'global',
+        target_id: 0
+      )
+    end
+  end
+
+  context 'when deleting the ghost user' do
+    let(:user) { ghost_user }
+
+    it 'returns an invalid user error' do
+      expect(service_response).not_to be_success
+      expect(service_response.payload[:error_code]).to eq(:invalid_user)
+      expect(User.exists?(ghost_user.id)).to be true
+    end
+  end
+
   context 'when current user lacks permission' do
     let(:current_user) { create(:user) }